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TOPIC: Jets over Salisbury Plain ll (warts and all)

Jets over Salisbury Plain ll (warts and all) 3 months 1 week ago #849

  • ahmetcalfe
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On Sunday I managed to get over once again to Salisbury Plain to do some Rapier flights, the weather was reasonably good with some sun, a 5 mph breeze and a temp of 8 degrees C. I particularly wanted to get my pals’ VC10 sorted out as well as my Stratojet as both were troublesome last time out, was I successful? :dry:



I tried the Stratojet first and once again I left off the engine nacelles as the initial test glide with them on showed that they came off rather too easily amongst the long grass stalks and were not easy to find.

The test glides all looked fine but under power with a supposedly L2LT (with 1.7mm bore) from a year or two ago, it was over powered and looped repeatedly - without coming to harm fortunately.:)
I think the power output must have been well over 150mN, unlike the older 110mN Rapiers, ouch. After changing the down thrust tab to a wider one I had the same troubles as last time out in that it had a nice wide spiral climb up followed by a wide spiral down in either direction while still under power. Eventually I got one decent flight with a lower powered Rapier (they do vary sometimes) but it still went into a gentle spiral down at the end.
It does look very good in the air so it has been worth the effort, but what is going on here? Do the long wings with the tips so far back interfere with the action of the tailplane and need reflexing, or does the flat wing need some dihedral; hmmm, not had trouble with anhedral wings before?:blink:



Next up was the profile VC10, this time out I had new better section leading edges to the wings, more tailplane negative incidence and more noseweight, with a new, bigger, tailplane in 1.5mm Depron foam, was well as a profile engine pod in the same material.
Although the test glides were good, when powered with the same uprated L2LT’s I could not get a decent flight pattern until I experimented by removing the profile engines and tried another flight. This time the model climbed quickly to a good height in wide smooth circuits, went into a slow serene and straight glide across the breeze looking a new exciting shape in the air, wow.:cheer:



Then it was the turn of Bill Dean’s Vulture which was the inspiration for the two models above, but this time the power was a little too much for it and proceeded to stall throughout the flight. Knowing that this model can be easily and quickly sorted out on the next outing I was impatient to get on with the F-4 Phantom, as the last time out it was real puzzle.



However, it proved even more out of trim than last time, and I failed to get better than a couple of low flights that ended with no glide at all - only a vertical dive into the ground. :S
Careful observation of some test glides that initially looked good, showed that it was slowing down and stopping in the air and sinking flat, vertically down onto the ground. I have seen this before and it indicated to me that the decalage had disappeared during storage, obviously the wings were getting twisted by the weight of the other models in the box. Sighting along the underside of the model revealed that both wings were no longer flat on their undersides but twisted a little so that both wing tips had too much washout. Because individual storage boxes for each model for my many models would take up too much space, I store them about six at a time loosely in one large box. I will have to put them in more carefully next time.



As I haven’t seen my all Depron foam Valiant in the air for some time I thought it would be good to give it an airing, but although it has flown very well in the past it is getting a bit old and crusty and misbehaved this time [Roger adds, like its owner :P ].
I found it was all due to a faulty repaired front fuselage making the model turn too much at speed leading to high speed tumble into the grass. No damage but it will need repairing for next time, it is such a nice flyer and a lovely shape in the air that I ought to build a new one, maybe this time in balsa like Pete’s VC10 and Vulture.



Lastly but no means least, I fished out my enlarged version of Bill Dean’s Spook and despite being in the bottom of the box for the last 3 or even four years, much to my amazement it flew perfectly. Again somewhat over powered with L2LT, it climbed up to about 150 feet almost vertically and then speeded round in a tight racetrack pattern right over my head for 3 or 4 circuits before gliding very slowly and sedately in a straight line. I had several such flights exactly the same then tried one with the launch banked to the left and it climbed up in a wide spiral to about 100 feet before going into the same high speed tight turns before a slow glide down. What more can you ask?

A few vital statistics of the two best flyers of the day:

Spook, 15.5” span, glide weight 15 grams, mostly firm 1/16th balsa with 1/8th balsa fuselage, waterproofed with printed T shirt material décor.

VC10, 15.5” span, glide weight, 22 grams, 1/8th medium balsa wings and fuselage, 1/16th Depron tailplane, no décor only Eze dope waterproofing.
Roger asks:
How many of your precious motors did you get through?


A lovely posting, Howard - you are an inspiration to us all. You are a real Prime Pilot!
The following user(s) said Thank You: rogersimmonds

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Last Edit: by rogersimmonds.

Jets over Salisbury Plain ll (warts and all) 3 months 1 week ago #850

  • ahmetcalfe
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I used nearly 30 Rapiers, practically all of which were L2LT's with 1.7mm or 1.8mm bores, powerful motors this time out despite the cold which usually affects the thrust adversely. When my igniter batteries needed replacing I tried a couple of fuses to ignite them but they only worked if warmed up between the finger tips first. Prime Pilot through Persistence perhaps, ha ha.

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